1. Field of the Invention
The present invention is an improved ambient temperature responsive bleed valve, which is compact and easily attachable to an external water faucet for the purpose of allowing water to be bled from the faucet in response to ambient temperature changes below and through a predetermined freeze point. The present invention is primarily a safety device, in that when there is a danger that the water within a household system may freeze, this device automatically relieves the pressure in a dripping fashion, so that freezing and bursting of the pipes of the household system will be avoided. The present invention has particular utility in those areas of the United States where a household water pipe system is not particularly designed for sudden and unexpectedly severe freezing conditions, i.e., where a relatively temperate climate is normal. For example, the Southeastern parts of the United States are particularly vulnerable to severe frosts, since the normally temperate climate of this region does not dictate that water pipes be sufficiently insulated or otherwise protected from ambient conditions to withstand such sudden sub-freezing conditions.
The present invention is a particularly simple and economical approach to providing automatic dripping of water from a faucet, in response to sudden freezing conditions, since no user adjustments are either required or possible. Hence, the significant object of the present invention is to provide an improved water drip device which will be both easily attachable to an exterior household water spigot, and also operate effectively without any possibility of breakdown due to user misadjustment or tampering.
2. Description of the Prior Art
Numerous devices are known in the prior art for allowing water within a household system, for example, to be somewhat flowed when there is a danger that ambient temperatures would freeze the pipes of the system. Representative of such prior art approaches known to the applicant are the U.S. Pat. Nos., as follows: Lowe 1,134,882; Egan 1,200,928; Opp 1,526,718; Peterson 1,558,276; Cartwright 1,916,038; Managhan 2,995,140; Morgan 3,320,965; Allderdice 3,369,556; Arterbury, et al. 3,380,464; Strange 3,397,711; Canterbury 3,446,226; Wismer 3,880,180; Nakajima, et al. 4,066,090.
Lowe is noted simply to illustrate an early system approach to the problem of water pipe freezing when a valve is configured to simply respond to a pressure drop, as the result of the constriction of water pressure which is created by a self-contained thermal sensing loop within the water pipe as it enters the house.
Egan illustrates an early freeze release valve construction which depends upon an aneroid spring mechanism, and requires manual resetting after a lever has opened the water line to a bleed position.
The patents to Opp and Cartwright show further water draining devices, and particularly integral valving mechanisms. In Opp, the valve member must be opened against the water pressure, so that drained water is ensured to freely surround the piston which is then moved by the expansion of the water, in a separate chamber.
Cartwright shows a container with a valve which will allow release of liquid from the container, in response to a freeze. Cooling fluid from the container is allowed to freeze in an exterior region, and then simply lift up the valve to relieve the pressure. Both Opp and Cartwright are clearly structurally inappropriate for simple mounting upon a male end of a spigot.
The patent to Managhan illustrates a valve construction, which is dependent upon the fracturing of a glass bottle, under freeze conditions. Managhan illustrates a one-shot device, wherein replacement of a glass bottle is required each time there has been a freeze.
The patent to Morgan illustrates a freeze protection dump valve construction which is configured to respond only to the combined conditions of a lowered line pressure, and a subfreezing ambient temperature. Consequently, Morgan significantly requires that the valve close whenever line pressure is greater than, for example, 10 PSI, despite any state of contraction for the ambient temperature responsive bellows which he employs.
The Allderdice patent illustrates a freeze device having a bellows filled with a liquid, such as water. Expansion of the fluid upon a freeze condition will actuate a valve off its seat, in a direction against the water pressure within a water line. Importantly, Allderdice requires his device to be mounted vertically and in-line with respect to the household plumbing; with by-pass water passing upwardly, through the device, to an ultimate discharge. Finally, Allderdice's device also requires a lost motion adjustment to ensure actuation, in complete distinction to the self-contained and non-adjustable device of the present invention.
The patent to Arterbury, et al. is pertinent to an appreciation of the present invention. Arterbury, et al. illustrates an elongated housing which includes an annual expansion chamber, and further a valve member which is hollowed to allow by-pass water to flow through the valve member to an ultimate discharge. Arterbury critically requires that his longitudinally movable valve member be constructed so the by-pass water will have a heat transfer effect upon the expansion chamber volume. For this purpose, Arterbury requires that a portion of the valve member extend into the household water path, in order to ensure that the thermal response of the expansion chamber is dependent upon the temperature of the household water supply. Further, the Arterbury device requires an in-line mounting to the water line, and he uses a fluid which has a positive coefficient of expansion for decreasing temperatures, unlike the negative coefficient required within the present device.
The patent to Strange illustrates a device for releasing water to prevent freezing, wherein contraction of a thermally responsive element opens the drip valve. While Strange illustrates a dump valve mounted upon a downwardly extending spigot, his valving actuator is a series of wafers configured to have a negative coefficient of thermal expansion in the vicinity of 0.degree. C. The present invention consists of significant improvement upon the approach of Strange, who critically teaches an external screw adjustment in order to ensure valve actuation, and the need for impinging by-pass water directly upon the wafer assembly, so as to override a contraction of the wafer due to simple ambient temperatures.
The patent to Canterbury is also considered pertinent to an understanding of the present invention, since he teaches an automatic device which is adapted for simple mounting on the male end of a spigot. In Canterbury the valve actuation is accomplished by a block of material which contracts upon lowered temperatures, and his block material is located so that the by-pass water will have an enveloping effect upon this thermal member. In distinction, the present invention employs a fluid volume, and does not either allow or lend itself to adjustment or tampering by the user. Moreover, the present invention maintains the volume of actuation fluid independent of water line temperature, so that a functioning reflects only an ambient temperature situation, and not any effects which are localized, due to contact of the drip water on the operating fluid medium.
The patent to Wismer teaches a water pipe freeze valve which employs a floating piston, within an extending housing, whereby expansion of water within the housing raises a piston and snaps open a valve which then opens a separately spaced drain tube. Wismer's construction is, firstly, not adapted to simple mounting on the male end of the spigot and, accordingly, his entire device requires that the piston have a port so that household water from above the piston will be ensured to fill his expansion fluid volume.
Finally, the patent to Nakajima, et al. illustrates a recent patent on a water cock having an integrally mounted non-freezing valve. This device operates on the principle of bringing relatively warmer line water up to the valve. This patent also begins with an ambient, local temperature, but then functions also in response to the household water temperature, reaching the valve.
The above patents represent the prior art as known to applicant, and collectively illustrate various approaches to the design of a freeze relief dump valve. Nonetheless, the present invention is considered to teach considerable improvement over the teachings of this prior art, in that it allows the ambient temperature to control whether or not the valve is open, without regard to a localized temperature increase from warm water being dripped out past the mechanism. The present invention thermally separates the household water supply from the functioning valve. Hence, a freeze condition in a separate part of the water line system will be prevented, even though there might not be a freeze condition within the water line proximate the attached device. Further, the present invention is sealed and does not allow user adjustment or tampering, and the invention significantly includes using a particular class of fluids as the contracting fluid, and a particular construction of fluid piston to ensure maximum excursion of the valve, during the drop through a critical temperature range. Moreover, if the closed volume of fluid is reduced, either through tampering or leakage, the present device is configured so that the valve will remain in an open position, and call attention to its non-functioning condition. In other words, the present invention includes a redundant safety factor, in that if the thermally contracting fluid is not truly filled and closed, the device will malfunction into an open, and therefore, safe position.